The present invention relates to an X-ray film cassette.
X-ray film cassettes are known in the art. A known X-ray film cassette has a body part, a cover part, a locking or connecting element for closing both cassette parts, at least one reinforcing foil, a magnetic plate having a size corresponding to the size of the film, a counterplate attractable by the magnetic force of the magnetic plate. An X-ray film and the reinforcing foil are held between the magnetic plate and the counterplate, and the magnetic plate and/or counterplate are elastically mounted on the respective cassette parts. Such a film cassette is disclosed, for example, in the German Offenlegungsschrift No. 2,802,730.7. It has been shown that in this cassette, after insertion of a new film and locking the cassette, particularly in the event of large size cassettes, an air pocket can form between the film and the reinforcing foil. This air pocket displaces after a certain time, because of the attractive force acting between the magnetic plate and the counterplate, to the edge and can open the latter. This can correspond to greater time than the time between the charging and the use of the cassette. This means that the X-ray exposure takes place in condition of an air pocket, which can lead to a not sharp region in the picture, depending upon the thickness of the air pocket.